Air Conditioning - Help a newb- ac doesn't come on

Hi,

I'm a student and I really don't know anything about a/c units or terms, so please bear with me.

I finally decided to use the air conditioner today after 6 months of using the heater only.

Well, I set the thermostat (digital) and I hear the click, so I thought the a/c would start blowing like it did in the past.

The fan outside (the big box sitting on the cement slab) started running....but even after 20 minutes, inside the condo the air was not turning on.
Usually there is some machine up above the shower that makes noise when the air starts running. It is completely silent....and no air is blowing.

Can someone tell me what the solution is? i will have to have a professional come do it, as I don't know anything. But I would at least like to know what the problem seems to be and a possible solution.

If I haven't used the air conditioner for over half a year, does it take a long time to turn on? Should I leave the thermostat set on Cold and let the outside fan keep running?


Sorry for the dumb questions and long post... I just found this forum and hope to get some insight !
Thank you !!

-Cheesefries

If you put the fan switch on the thermostat in yhe on position does the indoor blower run ?

If you put the fan switch on the thermostat in yhe on position does the indoor blower run ?

hi dun11,

The thermostat is digital.... the only options are Cool/Off/Heat and Auto/On

the other buttons set the temperature up and down.

Doesn't seem like the most advanced system...

I tried to reset the electrical box and test it again...still no luck.

I don't suspect the wiring in the thermostat because just last year the a/c was running fine, and I haven't touched anything around the wiring.

Thoughts?

I think the implication is we all want to simply know for the moment if the blower can even run?

So, does it come on when you set it to heat + auto?

Then what about setting it to cool OFF heat + auto ON. (The right settings that say auto and on, allows you to choose to either have the blower come on automatically with a call for heat or a/c -or- the choice to have the fan blow constantly, no matter what the left 3 settings are set at.

I think the implication is we all want to simply know for the moment if the blower can even run?

So, does it come on when you set it to heat + auto?

Then what about setting it to cool OFF heat + auto ON. (The right settings that say auto and on, allows you to choose to either have the blower come on automatically with a call for heat or a/c -or- the choice to have the fan blow constantly, no matter what the left 3 settings are set at.


Thank you for clarifying.

Heat + Auto = works
OFF (cool/off/heat) + On (auto/on) = no work
cool + auto or on = no work (well, the fan OUTSIDE works, but no air inside)

What does this mean?

The indoor blower motor is 120V. and would be on a single handle, single pole breaker. Make sure it's not tripped, or off. Make sure the switch at the air handler in the attic is on. While you're up there, change the filter through an access panel or vertical strip.
You may even see a reason why the blower isn't turning: like a rodent nest, filter pulled into the blower or disconnected wire/bad capacitor. (Bring a flashlight)
Tom Beer 4U2

Heat + Auto = works


So the blower motor runs in the heat mode ?

What does this mean?

It means we are honing in on possible causes, and that if you are desperate for it to work, that if you can check the messages often, you may get responses and more questions from people who can help.

Specifically, we have been trying to figure out if your inside house blower can even work, for any setting of the themostat, since you never said in your opening post (OP) that it has been able to come on.

An inside blower fan, with your stat, and if wired up for all it's functions, should be able to come on in one of 4 ways: By only having the fan run, by setting the left setting OFF and right setting ON; or blower is supposed to also be able to run when set to either HEAT and AUTO, or COOL and AUTO, as long as you turn the stat way up for heat and way down for coo; and, where if you have the right setting on the stat to ON, then the blower will always blow if it is set to HEAT or COOL, even if there is no 'calling' for HEAT or COOL.

So the blower motor runs in the heat mode ?

Yes, heat + auto keeps the temperature where I set it. Inside blower comes on to maintain the set temp.

Cool + auto or cool + on is not working.
OFF + ON is not working either.

Hope this explains it better.

Do you own a voltmeter? If not, they can be bought for real cheap, like under $4 at Harbor Freight stores, if you have one of those nearby. And at home centers perhaps near $10. A voltmeter can save you hundreds of dollars in repairs where you can diagnose, then fix things yourself.

I'd like to know if you have 24 volts when the 2 probes are placed one on the G terminal and the other probe to any ground on the furnace itself, when the furnace is set to heat OFF cool and to auto ON. This test would show if the correct voltage is at least making it's way through the thermostat and trying to energize components in the furnace.

The test I mention would be done on this strip in the bottom part of the furnace where you see a strip bar with skinny different color wires attached to terminals that say R,W,Y,G, etc.

I'm thinking the G(fan) connection is not being made somewhere between or in stat and furnace. It can run on heat/ auto without it (as a R and W only furnace will attest to).

As "51" said, you will need a meter (and be able to use it) to go any further

Sounds like an "over the tub" air handler commonly used in multi-unit housing. Probably made by First Co. or Goodman.

If I'm correct (about the type of unit), and the blower works in heating mode but not in A/C mode, then my money would be on a bad blower relay. In heat mode, the blower is powered by the heat sequencer through the normally closed contacts of the blower relay. In A/C mode, blower power is derived through the second set of contacts (normally open) in the blower relay. These units typically use 240 volt motors.

To diagnose further, you will need a meter and know how to use it.

Alternatively, you may have a bad or miswired thermostat. Was the thermostat recently replaced?

Sounds like an "over the tub" air handler commonly used in multi-unit housing. Probably made by First Co. or Goodman.

If I'm correct (about the type of unit), and the blower works in heating mode but not in A/C mode, then my money would be on a bad blower relay. In heat mode, the blower is powered by the heat sequencer through the normally closed contacts of the blower relay. In A/C mode, blower power is derived through the second set of contacts (normally open) in the blower relay. These units typically use 240 volt motors.

To diagnose further, you will need a meter and know how to use it.

Alternatively, you may have a bad or miswired thermostat. Was the thermostat recently replaced?


Hi,
Thank you all for the replies.

Yes, the thermostat was replaced just last year. At that time we tested the heat AND the a/c , and both worked fine. Since then I have only used the heater and not the a/c. Now the heater still works, but a/c does not.

I guess I'm stuck here. i do not own a voltmeter; I have never used one in my life, so buying one would be no use since I don't know how or where to use it. :( It is frustrating that I don't understand any of the tests you want me to run, but that is all my own lack of knowledge. I appreciate all the help thus far.

I will keep you all updated when the repair guy comes.

I guess I'm stuck here. i do not own a voltmeter; I have never used one in my life, so buying one would be no use since I don't know how or where to use it. :( It is frustrating that I don't understand any of the tests you want me to run, but that is all my own lack of knowledge. I appreciate all the help thus far.

I will keep you all updated when the repair guy comes.

I did not know how to use one either, years ago. I just bought one and found out. You have to possess an 'I- can- fix- anything- I- put- my- mind- to mentality, if you want to be a good DIY'er. That is half the battle.

Confidence, curiousity, a willingness to listen to what someone says that can instruct, etc.

We could walk you through tests. By not owning a voltmeter, you are selling yourself short, and opening yourself up to hundreds upon hundreds of $'s of repair costs.

You can test small DC batteries, car batteries, alternators, starters, relays, run down shorts or disconnedcts in wiring, see if current is going through switches, see if oven and range elements are burned out or not or if full current is making it's way to an appliance.

Uses are for all batteries, cars, water heaters, ranges, refrigerators, washers, dryers, furnaces and a/c units, house circuits, light bulbs and sockets, etc. And then you can replace the parts yourself and save a fortune.

Have you read some of the horror stories as to what some members here have had to pay the pro for for just dioagnosing, and for also the what I consider quite DIY-able repairs? Some are outrageous.

23 years ago I started working on mobile home furnaces. Nobody showed me how. I just applied my stubborn will -not -be -defeated attitude (the same I had when it came to trying to figure out car problems, and doing the work for the first time, also) started guessing at what parts connected to wires had to do. Like if a thremodisc went out and furnace got stuck. Or if a thermocoupling went out and stopped the fire. And even when blowers started going out I just looked at how they could come out of the furnace and did the work.

You have to have that attitude. And your attained knowledge will set you free.

It's a start in the right direction. One must always be wise enough though to always question so that you do not have misguided confidence where you are only smart enough to be dangerous.